Can you date your friends dad?
You would not be a bad person for dating your friends dad so long as everyone involved is okay with it, but you would still be a very foolish person for getting into such a potentially volatile situation.
Is it bad to date a dad?
Theres absolutely nothing wrong with that. Its better to know your limits from the beginning. However, plenty of women enter relationships with fathers willingly. Some women may think theyre fine dating a dad, but the deeper they get into the relationship, the more they realize theyre not so into it.